Rotating Disc for Machining Material Surfaces

ABSTRACT

Proposed is a method for producing a rotating disc for machining material surfaces, said disc comprising a disc-shaped main body ( 10 ), which has a central receptacle ( 14 ) for direct or indirect connection to a drive shaft, and a material machining coating ( 18 ), which is applied to a ring zone ( 12 ) of the main body ( 10 ) that is arranged on an end face, comprising the following steps:
         placing glass fabric mats in a mold cavity of a production tool;   compressing the glass fabric mats in the production tool to form the main body ( 10 ) having a lip ( 16 ) which is configured in a section at least close to the edge;   demolding the main body ( 10 );   applying the material machining coating ( 18 ) to the end face of the main body that faces away from the lip ( 16 );   stacking main bodies ( 10 ) of the same kind, each having a material machining coating ( 18 ) applied thereto, so that the lip ( 16 ) of one main body ( 10 ) is directly supported on the material machining coating ( 18 ) of a next main body ( 10 );   exerting a pressure on the stack of main bodies ( 10 ), each of which has the material machining coating ( 18 ) applied thereto, parallel to the rotation axis of the main bodies ( 10 );   releasing the pressure and destacking the main bodies ( 10 ) which have the material machining coatings ( 18 ) applied thereto.

The invention relates to a method for producing a rotating disc for machining material surfaces, to a rotating disc for machining material surfaces and to a tool for producing a main body of a rotating disc for machining material surfaces.

Rotating discs for machining material surfaces are known in practice especially in the form of a grinding tool with a disc-shaped main body via which the rotating disc can be powered and faced with a material machining coating. The material machining coating can be formed from separate flaps of abrasive paper or abrasive fabric secured to one end face of the main body configured overlapping circumferentially.

Known furthermore is to form the main body of rotating discs of the aforementioned kind of glass fabric mats. For this purpose the separate portions of the glass fabric mats are stacked in a mold cavity and compressed to interconnect with the use of a casting resin. Due to the structure of the glass fabric mats the resulting main body is substantially the same in thickness throughout, i.e. with no sudden change in thickness.

In series production of rotating discs for machining material surfaces configured as flap abrasive discs the main bodies faced with the material machining coating are stacked on a centering rod passing through a central opening in the main body. Between the individual rotating discs a so-called burner plate is inserted to ensure when compressing the rotating discs axially oriented as to the rod each of the rotating discs of the material machining coating is pressed against the corresponding main body both centrally and close circumferentially to attain good bonding of the material machining coating over the full surface of the rotating disc by compression.

It was found out, however, that making use of burner plates in producing rotating discs is time-consuming and also cost-intensive.

This is why the invention is based on the object of eliminating the aforementioned drawbacks.

This object is achieved by the method for producing a rotating disc for machining material surfaces having the features as recited in claim 1.

In accordance with the invention, therefore, a method for producing a rotating disc is proposed comprising a disc-shaped main body, which has a central receptacle for direct or indirect connection to a drive shaft, and a material machining coating, which is applied to a ring zone of the main body that is arranged on an end face, comprising the following steps:

-   -   placing glass fabric mats in a mold cavity of a production tool;     -   compressing the glass fabric mats in the production tool to form         the main body having a lip which is configured in a section at         least close to the edge;     -   demolding the main body out of the production tool;     -   applying the material machining coating to the end face of the         main body that faces away from the lip;     -   stacking main bodies of the same type, each having a material         machining coating applied thereto, so that the lip of one main         body is directly supported on the material machining coating of         a next main body;     -   exerting a pressure on the stack of main bodies, each of which         has the material machining coating applied thereto, parallel to         the rotation axis of the main body; and     -   releasing the pressure and destacking the main bodies which have         the material machining coatings applied thereto.

Now, thanks to the method in accordance with the invention in which the main body is configured or formed with a supporting lip it is possible to do away with the need for burner plates when compressing or bonding the material machining coatings to the corresponding main bodies. Instead, the main bodies composed of glass fabric mats are supported by the supporting lips directly at the adjoining rotating disc so that the pressure needed to bond the material machining coatings can now be reliably applied as required.

In one special embodiment of the method in accordance with the invention the stack of main bodies when exerting a pressure is heated so that an adhesive is activated for bonding each material machining coating to the corresponding main body. As an alternative it is just as possible to use two-component or moisture-curing adhesive systems with which, where necessary, there is no need to heat the stack.

To achieve neat stacking of the main bodies the stack of main bodies, each of which has the material machining coating applied thereto, is centered by means of a rod passing through the central receptacle of the main body.

So as not to expose a later user of the rotating disc produced by the method in accordance with the invention to an added risk of injury the lips of the main body are smoothed or deburred. Smoothing the lips is preferably done before stacking the main bodies or before facing the main bodies with the material machining coating so that, in addition, when compressing the material machining coatings or stacking the main bodies the main bodies feature a clean and even pressure edge circumferentially.

The invention also has the object of a rotating disc for machining material surfaces, said disc comprising a disc-shaped main body, which has a central receptacle for direct or indirect connection to a drive shaft, and a material machining coating, which is applied to a ring zone of the main body that is arranged on an end face, the main body being made of glass fabric mats and featuring a lip which is configured in a section at least close to the edge at the side facing away from the material machining coating, said lip configured surrounding at least in part.

The lip renders the main body more rugged besides, as already explained above in conjunction with the method in accordance with the invention, making it easier when bonding the material machining coating to compress it to the main body.

The thickness of the main body is constant over its main surface, i.e. even in the region of the lip there is no sudden change in thickness.

In another preferred embodiment of the rotating disc in accordance with the invention the lip is configured fully surrounding. As an alternative the lip may also be configured portion-wise circumferentially as regards the main body.

The lip may also be arranged at diverse positions of the main body. On the one hand the lip may rim the main body, the rim of the main body then directly forming the edge exerting pressure when stacking the main bodies for bonding the material machining coating.

As an alternative the lip may take the form of a bead in the structure of the glass fabric material and spaced away from the rim of the main body. The bead may feature a V, U or tub-shaped cross-section, its base then forming on compression of the each material machining coating to the main body the area or line on the material machining coating of the adjoining rotating disc.

The material machining coating may also be formed by a plurality of abrasive flaps in an overlapping arrangement on each end face of the main body.

Depending on what is practical the main body may have a diameter ranging from 90 mm to 230 mm and as a function of the geometry of the rotating disc or of the main body or the thickness of the material machining coating applied to the main body, the lip may have a height ranging from 1 mm to 8 mm.

The invention also has as its object a tool for producing a main body of a rotating disc for machining material surfaces formed of a plurality of interconnected glass fabric mats, the tool comprising a mold cavity to nest the glass fabric mats corresponding in shape to that of the main body and a portion for configuring an at least partly surrounding lip of the main body.

To produce the main body in addition to the glass fabric mats, for example, a casting resin or the like interconnecting the individual glass fabric mats is introduced into the mold cavity.

Producing the lip of the main body is achievable particularly in that the portion for configuring the lip is a kink formed cross-sectionally in the edge of the mold cavity.

To configure a bead in main body the portion for configuring the lip can have the form of a wavy bend close to the edge cross-sectionally of the mold cavity.

It is also possible that the rotating disc comprises a plurality of lips spaced away from each other in the radial direction of the main body, the tool for producing the main body then correspondingly featuring a kink and at least one or more wavy bend(s) of the aforementioned kind.

Further advantages and advantageous aspects of the subject matter of the invention read from the description, as shown in the drawing and from the claims.

Example embodiments of a rotating disc in accordance with the invention and a method for producing a rotating disc in accordance with the invention are shown diagrammatically in the drawing as detailed in the following description, wherein

FIG. 1 is a top-down view of the main body of a rotating disc in accordance with the invention;

FIG. 2 is a section through the rotating disc as shown in FIG. 1 taken along the line II-II in FIG. 1;

FIG. 3 is a magnified view of the portion III in FIG. 2;

FIG. 4 is a section through a rim portion of an alternatively configured main body;

FIG. 5 is a section through a main body configured in a further alternative; and

FIG. 6 is a view of the stacking process when bonding a material machining coating to the main body.

Referring now to FIGS. 1 to 3 there is illustrated a main body 10 of a rotating disc for machining material surfaces, representing an abrasive flap disc featuring in the finished condition a plurality of circumferentially overlapping abrasive flaps on a ring zone 12 forming a material machining coating. In the middle the main body 10 features a central receptacle 14 serving to directly or indirectly receive a drive shaft via which the rotating disc can be rotatingly powered.

The main body 10 with a diameter of, for example, 120 mm is formed of glass fabric mats, each compressed or bonded to the other so that the main body 10 has no sudden change in thickness laterally, it instead being constant in thickness.

The main body 10 is furthermore rimmed by a lip 16 which cross-section forms an at least approximately L-shaped kink in the main body covering the full circumference.

In the main body 10 as shown in FIGS. 1 to 3 the plane of the ring zone is configured at right angles to the axis of rotation. As an alternative, however, the ring zone may also be configured curved or downswept outwardly.

Referring now to FIG. 4 there is illustrated an alternative embodiment of a lip 16′ rimming a main body 10′. The lip 16′ has the shape of a bead of the main body 10′ and features a substantially V-shaped cross-section. The radial outer flank of the bead forms the rim of the main body 10′.

Referring now to FIG. 5 there is illustrated a further alternative embodiment of a circumferential lip 16″ of a main body 10″. Likewise the lip 16″ is formed of a ring-shaped bead of the main body 10″ spaced away from the rim of the main body 10″.

In producing a rotating disc featuring the main body as shown in FIGS. 1 to 3 after production of the corresponding main body the ring zone 12 of the main body 10 is coated with the flap assembly 18 representing the material machining coating, an adhesive system being interposed between the flap assembly 18 and the main body 10. Prior to coating the main body with the flap'assembly 18 the edges of the main body 10, i.e. the supporting lips 16 are finished by grinding and deburring.

Referring now to FIG. 6 there is illustrated how then main bodies 10 all of the same kind, each coated with a flap assembly 18 are stacked on a centering rod 20 so that a lip 16 of a main body 10-1 supports on the flap assembly 18 a next rotating disc with a main body 10-2.

Producing rotating discs with the main bodies 10′ and 10″ as shown in FIGS. 4 and 5 is done correspondingly.

After stacking the main bodies 10-1, 10-2 coated with the flap assemblies 18 a pressure F is exerted parallel to the axis of the rod 20 during which the structure is heated so that the adhesive system interposed between each flap assembly 18 and each main body 10 is activated.

The pressure F is then released so that the main bodies coated with the material machining coatings can be unstacked. 

1. A method for producing a rotating disc for machining material surfaces, said disc including a disc-shaped main body, which has a central receptacle for direct or indirect connection to a drive shaft, and a material machining coating applied to a ring zone of the main body that is arranged on an end face, said method comprising the following steps: placing glass fabric mats in a mold cavity of a production tool; compressing the glass fabric mats in the production tool to form the main body having a lip which is configured in a section at least close to the edge; demolding the main body from the mold cavity of the production tool; applying the material machining coating to the end face of the main body that faces away from the lip; producing more than one main body to form a plurality of main bodies and stacking said plurality of main bodies, each main body of said plurality of main bodies having a material machining coating applied thereto, so that the lip of one main body of said plurality of main bodies is directly supported on the material machining coating of a next main body of said plurality of main bodies; exerting a pressure on the stack of main bodies, each of which has the material machining coating applied thereto, parallel to a rotation axis extending through the central receptacle of the main body; releasing the pressure and destacking the main bodies which have the material machining coatings applied thereto.
 2. The method as set forth in claim 1, in which said stack of main bodies when exerting a pressure is heated so that an adhesive is activated for bonding each material machining coating to the corresponding main body.
 3. The method as set forth in claim 1, in which said stack of main bodies each of which has the material machining coating applied thereto is centered by means of a rod passing through the central receptacle of the main body.
 4. The method as set forth in claim 1, in which said lips of the main bodies are finished smoothened.
 5. A rotating disc for machining material surfaces, said disc comprising: a disc-shaped main body, which has a central receptacle for direct or indirect connection to a drive shaft; and a material machining coating applied to a ring zone of the main body, said ring zone being arranged on an end face of the main body, the main body being made of glass fabric mats and featuring a lip which is configured in a section at least close to an edge of a side facing away from the material machining coating, said lip surrounding said central receptacle at least in part.
 6. The rotating disc as set forth in claim 5, in which said lip is fully surrounding said central receptacle.
 7. The rotating disc as set forth in claim, in which said lip forms a rim of the main body.
 8. The rotating disc as set forth in claim 5, in which said lip is a bead in the structure of the glass fabric material and spaced away from the rim of the main body.
 9. The rotating disc as set forth in claim 5, in which said main body has a diameter ranging from 90 mm to 230 mm and the lip a height ranging from 1 mm to 8 mm.
 10. A tool for producing a main body of a rotating disc for machining material surfaces formed of a plurality of interconnected glass fabric mats, the tool comprising a mold cavity to nest the glass fabric mats corresponding in shape to that of the main body and a portion for configuring an at least partly surrounding lip of the main body.
 11. The tool as set forth in claim 10, in which said portion for configuring the lip is a kink formed cross-sectionally in the edge of the mold cavity.
 12. The tool as set forth in claim 11, in which said portion for configuring the lip is a bend having a wavy cross-section and being close to the edge of the mold cavity. 